Tag: tornadoes

Climate: Are tornado outbreaks becoming more frequent?

A new NOAA study tracks the occurrence of seasonal tornadoes across the U.S.
Severe tornado outbreaks across the U.S. are increasing. Photo courtesy NOAA.

Average number of tornadoes per outbreak has increased by 50 percent since 1954

Staff Report

Forecasting tornadoes has never been easy, and when you add global climate change to the equation, it becomes even murkier. In some studies, researchers say they haven’t been able to pinpoint any long-term trends in tornado activity, while other research suggests tornado seasons are becoming more variable.

In one recent 10 year period, tornadoes in the United States resulted in an average of 110 deaths per year and annual losses ranging from $500 million to $9.6 billion, so trying to establish patterns and improve forecasting models is not just an idle mathematical exercise.

A new examination of tornado records during the past 60 years indicates that tornado outbreaks (six or more tornadoes during a limited time) have become more frequent. Such outbreaks result in the largest numbers of deaths and injuries, as well as the most property destruction. The study, published recently in Nature Communications, also shows that mathematical models show the chance of such extreme events is growing over time. Continue reading “Climate: Are tornado outbreaks becoming more frequent?”

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Climate: Does La Niña increase the odds of tornadoes?

Finding a signal amidst the climate noise isn’t easy

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Does La Niña increase the odds of tornadoes?
A new NOAA study tracks the occurrence of seasonal tornadoes across the U.S.
Study finds links between ENSO and tornado frequency in the Southern U.S. Photo courtesy NOAA.

Staff Report

FRISCO — Teasing out a link between large-scale atmospheric patterns and specific weather events isn’t easy against the backdrop of natural variability.

But a new study of the El Niño-La Niña cycle in the Pacific Ocean suggests that La Niña — the cool phase of the cycle — increases the frequency of tornadoes and hail storms in some of the most susceptible regions of the United States.

During La Niña, both vertical wind shear and surface warmth and moisture increase significantly in the southern states, making conditions favorable to severe storm occurrence.

The study, published in the current issue of the journal Nature Geoscience, may help provide more information for medium- and long-range extreme weather forecasts. Continue reading “Climate: Does La Niña increase the odds of tornadoes?”

Climate: Study shows how smoke from distant wildfires can affect tornado formation

A tornado near Lakeview, Texas. Photo courtesy NOAA.
A tornado near Lakeview, Texas. Photo courtesy NOAA.

New study could help produce better tornado forecasting

Staff Report

FRISCO — Under certain conditions, wildfire smoke transported thousands of miles can intensify tornadoes in U.S., according to University of Iowa researchers, who studied how smoke from agricultural burning in Central America affected tornado conditions in the United States.

The research specifically looked at the smoke impacts on an April 27, 2011 tornado outbreak that spawned 122 twisters, killing 313 people, considered the most severe tornado event since 1950. Continue reading “Climate: Study shows how smoke from distant wildfires can affect tornado formation”

U.S. Tornado activity again below normal in 2014

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Tornado numbers low for third year in a row.

Scientists say they can’t pinpoint and long-term trends

Staff Report

FRISCO — The number of tornadoes in the U.S. was below average for the third year in a row, NOAA scientists said last week. A preliminary count shows there were about 800 tornadoes in 2014, the lowest number since 1982 and about 20 percent below the long term average. Continue reading “U.S. Tornado activity again below normal in 2014”

Study: Tornado season becoming more variable

A new NOAA study tracks the occurrence of seasonal tornadoes across the U.S.
A new NOAA study tracks the occurrence of seasonal tornadoes across the U.S.

Fewer outbreaks, but more twisters?

Staff Report

FRISCO — Tracking tornado trends is a big deal in the global warming era, as researchers seek to determine whether climate change will result in more catastrophic and life-threatening weather events.

Since the 1950s, researchers say, the overall number of annual tornadoes has remained steady, but a new analysis of data shows  there are fewer days with tornadoes each year, but on those days there are more tornadoes.

A consequence of this is that communities should expect an increased number of catastrophes, said lead author Harold Brooks, research meteorologist with the NOAA National Severe Storms Laboratory. Continue reading “Study: Tornado season becoming more variable”

New study shows link between Pacific sea surface temperatures and tornado patterns in the Midwestern U.S.

Cooler Pacific Ocean temps may drive tornado activity into southern U.S.

A tornado near Lakeview, Texas. Photo courtesy NOAA.
A tornado near Lakeview, Texas. Photo courtesy NOAA.

By Summit Voice

FRISCO — After studying more than 56,000 tornados, researchers at the University of Missouri say they’ve found a clear link between Pacific Ocean sea surface temperatures and the patterns of storms that spawn the violent twisters. The findings could help scientists predict the type and location of tornado activity in the U.S.

When surface sea temperatures were warmer than average, the U.S. experienced 20.3 percent more tornadoes that were rated EF-2 to EF-5 on the Enhanced Fuijta (EF) scale. (The EF scale rates the strength of tornados based on the damage they cause. The scale has six category rankings from zero to five.)

“Differences in sea temperatures influence the route of the jet stream as it passes over the Pacific and, eventually, to the United States,” said Laurel McCoy, an atmospheric science graduate student at the MU School of Natural Resources. “Tornado-producing storms usually are triggered by, and will follow, the jet stream. This helps explain why we found a rise in the number of tornadoes and a change in their location when sea temperatures fluctuated.” Continue reading “New study shows link between Pacific sea surface temperatures and tornado patterns in the Midwestern U.S.”

New satellites may lead to earlier tornado warnings

Tracking lighting inside clouds helps predict tornado formation

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Earlier tornado warnings could help save lives. Photo courtesy NOAA.

By Summit Voice

SUMMIT COUNTY — New satellite technology that can detect lightning inside clouds and track cloud formation may help weather forecasters develop earlier warnings for severe weather, especially tornadoes.

The national average for tornado warnings is 14 minutes. More time would give people in harm’s way a better chance to protect themselves, said the NOAA and NASA scientists working on the new GOES-R technology. The satellites will be able to monitor thunderstorm development with more temporal and spatial detail. Continue reading “New satellites may lead to earlier tornado warnings”